Note that the Comichron numbers are copies ordered rather than copies sold to end customers. It is more likely that the retailers will be hit economically by Heroes in Crisis than that DC will, at least in the short term.
I generally like to read reviews and criticism, and I find the state of comic book reviewing to be very poor. Most are little more than plot synopsises together with some unreflective opinions. A lot of reviewers don't seem to be aware of, or have reflected on, their own personal tastes and biases. Worse, too few try to discuss the story based on what it wants to accomplish and how well it manages that.
There are of course good exceptions. Ray Goldfield over at Geekdad is one—he regularly tries to dig into the themes of each story.